The present invention relates to the subject of providing protective coatings to metallic substrates. It relates more particularly to providing coatings to ferrous and non-ferrous products, and particularly steel products, to protect them from corrosion and abrasion.
It is, of course, widely recognized that articles of ferrous and non-ferrous metal find a wide variety of applications in the modern world and that in the overwhelming majority of those applications the metal is subject to abrasion, corrosion, or both over time. Thus, it has become necessary to fashion protective layers or coatings to prolong the life of the metallic substrate.
A particularly problematic aspect of the susceptibility of metal to corrosion arises when the metallic substrate in question is intended to be used in construction. It is typical that metallic articles, such as bees, girders, coils, pipe sections, and the like are placed at a construction site a substantial period of time before they will all be used or incorporated into the construction. The articles are thus exposed for an often considerable length of time to the corrosive effects of the atmosphere. Then, when the article is finally to be used, it is often necessary to invest additional time and energy in removing some or all of the accumulated corrosion from the article.
It has not been unrecognized that an appropriate coating applied to such articles before they are exposed to a corrosive atmosphere might alleviate the aforementioned problems. Traditionally, solvent-based lacquers and varnishes have been the materials of choice for putting anti-corrosion coatings onto e.g. steel pipe sections. These coatings are primarily employed to prevent the pipes from rusting during storage. These lacquers and varnishes are typically sprayed, flooded or poured onto the metallic substrates. However, such coating systems exhibit several deficiencies. Among these is a risk of fire. This risk is due to several factors; one factor is the high flammability of the solvent and of the lacquer or varnish components. In addition, spraying such a relatively fluid product necessarily disperses the lacquer or varnish into the vicinity around the metallic substrate as well as onto the metallic substrate itself, which increases the potential of exposure to a source of ignition. Spraying such material also atomizes the fluid, which increases all the more the susceptibility of the product to ignition and conflagration.
In addition, solvent-based lacquer and varnish systems represent a major source of emissions of the volatile organic compounds employed in the solvent system. Indeed, such systems particularly comprise 50 to 75% solvent. It will be appreciated that the volatilization of such substances poses environmental and health risks, which are of ever-increasing concern to society.
Thus, there is a need for a material which is capable of readily forming a corrosion-deterring protective coating on metallic substrates such as steel parts, and does so without posing safety, environmental or health risks to the user or to the surrounding environment.